Process of making cellulose fibers containing ether groups and beta-propiolactone substitutents



United States Patent 1 O 2,724,633 PROCESS OF MAKING CELLULOSE FIBERS CON- TAINING ETHER GROUPS AND BETA-PROPIO- LACTONE SUBSTITUENTS No Drawing. Application May 14, 1954, Serial No. 430,001

8 Claims. c1. 8--120) (Granted under Title 35, U. S. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, for all governmental purposes, throughout the world, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to a process of chemically modifying cellulose fibers. The invention provides fibers composed essentially of cellulose ethers and beta-propiolactone reaction products combined with cellulose, and provides an improved process of modifying cellulose fibers by reaction with beta-propiolactone.

This application is a continuationimpart of our copending applications, Serial Nos. 299,772 and 393,523 filed July 18, 1952, and November 20, 1953. 1

Our copending application No. 299,772 relates to reacting cellulose fibers with beta-propiolactone at a temperature of from about 50 to 155 C. until fibers are produced containing from about 0.5 to 26%, based on the Weight of the original cellulose fibers, of beta-propiolactone reaction products combined with the cellulose, i. ,e., about from 0.5 to 26% beta-propiolactone substituents. The substituted fibers so produced have markedly increased effective diameters, decreased affinity for water and polar compounds, and have a tensile strength not materially less than that, of the fibers from which they are produced. They have a dye resistance, heat resistance, acid induced degradation resistance, wrinkle resistance, and wool-like properties markedly greater than those of the fibers fromwhich they are produced. And, where desired, they can be converted to fibers containing an appreciable proportion ofolefinic unsaturated groups.

, A primary object of the present invention is to provide chemically modified cellulose fibers containing beta-propiolactone reaction products combined with the cellulose, which fibers have a heat resistance and acid degradation resistance greater. than those of thefibers containing beta-propiolactone reaction products combined with cellulose heretofore known. A further object is to provide a process of producing fibers containing beta-propiolactone reaction products combined with cellulose, in,

which process the fibers exhibit an enhanced reactivity towards the beta-propiolactone. A further object is to provide chemically modified cellulose fibers containing beta-propiolactone reaction products combined with cellulose, in which fibers the somewhat wool-like properties of cellulose fibers containing beta-propiolactone reaction products combined with cellulose are modified by properties such as the altered dyestufi susceptibility, affinity for water. (mold resistance, and the like which are imparted to cellulose fibers by an etherification yielding a cellulose ether containing polar alkyl radicals.

in general, according to this invention, cellluose fibers containing ether groups and beta-propiolactone reaction products combined with cellulose are produced by etherifying cellulose fibers with an etherifying agent selected from the group consisting of aminoalkyl sulfuric acid wherein the aminoalkyl radical is theetherifying radical,

Z-aminoethyl sulfuric acid being preferred, monochloroacetic acid wherein the carboxyalkyl and alkali metal carboxyalkyl radicals are the etherifying radicals, alkylene oxide wherein the hydroxyalkyl radical is the etherifying radical, ethylene oxide being preferred, acrylonitrile wherein the cyanoalkyl radical is the etherifying radical, and alkyl sulfate wherein the alkyl group is the etherifying radical, dimethyl sulfate being preferred, the alkyl group in each of said etherifying radicals having from 1 to 3 carbon atoms, until etherified cellulose fibers containing from about 0.1 to 2.5 of the said etherifying radicals of said etherifying agent per anhydroglucose unit is produced, and reacting the said etherified cellulose fibers with beta-propiolactone at a temperature of from 0 C. to a temperature slightly below the decomposition temperature of the fibers until fibers are produced containing from about 0.5 to 26%, based on the weight of the etherified fibers, of beta-propiolactone reaction products combined with the cellulose. Such fibers are composed of cellulose ethers containing, per each anhydroglucose unit, from about 0.1 to 2.5 radicals selected from the group consisting of aminoalkyl, alkali metal carboxyalkyl, carboxyalkyl, hydroxyalkyl, cyanoalkyl, and alkyl radicals, the alkyl group in each of said radicals having from lto 3 carbon atoms, and containing from about 0.5 to 26%, based on the weight of thecellulose ethers, of beta-propiolactone reaction products combined with cellulose.

When the etherified cellulose fibers are reacted with beta-propiolactone, their increased weight is essentially due to the introduction of beta-propiolactone reaction products within the walls of the fibers. This is true whether the etherified fibers are reacted with vapors of beta-propiolactone, or with beta-propiolactone in a liquid solution, in the presence or absence of a solvent or a catalyst, or in the presence of an acidic or a basic catalyst.

Cellulose fibers which can be used include cotton fibers such as lint, linters, and the like, and regenerated cellulose fibers such as viscose rayon fibers, before or after bleaching, mercerization, and the like treatments. Cotton fibers are preferred.

The cellulose fibers can be reacted in the form of ,free fibers, sliver, yarn, or fabric. The use of yarns, threads or cloth is preferred.

The etherification can be conducted in a variety of ways. For example, an etherification yielding ethers containing aminoalkyl radicals can be accomplished by reacting cellulose fibers with an aminoalkyl sulfuric acid in the presence of aqueous alkali metal hydroxide, by a process such as that described in U. S. Patent No. 2,459,222; one yielding ethers containing alkali metal carboxyalkyl radicals, or carboxyalkyl radicals, by reacting the fibers With monochloroacetic acid, by a process such as those of U. S. Patents Nos. 2,448,153, 2,617,707, or 2,663,615, and neutralizing the ether salt to yield the ether acid, where desired; one yielding ethers containing hydroxyalkyl radicals, by reacting the fibers with an alkylene oxide in the presence of aqueous alkali metal hydroxide, by a process such as is described in J. Soc. of Dyers and Colourists, volume 56, pp. 6-17, January 1940; one yielding cyanoalkyl radicals, by reacting the fibers with acrylonitrile in the presence of aqueous alkali metal hydroxide, by a process such as those described in U. S. Patent No. 2,375,848 or 2,473,308; and one yielding alkyl radicals, by reacting the fibers with an alkyl sulfate in-the presence of aqueous alkali metal hydroxide, by a process such as is described in Textile Research Journal, volume 19, pp. 771-783, December 1949.

The etherification, particularly when the cellulose fibers are cotton fibers, is preferably one yielding ethers containing from about 0.1 to 1.0 aminoethyl or alkali metal- Patented Nov. 22, 1955 amaxmethyl adicals. nwhih. wt qufibqrs. ar reac ed.

with ethyl sulfuric acid or monochloroacetic acid in the presence of aqueous sodium hydroxide.

The. eth r ed; fi-b'ers. can. be.v reacted, with. beta-propi olactone, solutions containing,bcta propiolactone, or the.

vapors of betamropiolactonejor beta-propiolaetone containing solutions. The fibers arepreferably reacted by immersing them in a beta-propiolactone containingcliquid maintained, atfrorn about C. toa temperatureslightly below, the, decomposition temperature. of the etherified fibers. -The betamropiolactoneicontaining liquid can be iquidv et rp pn olac o' e. or solutionot betwprop tone, The reaction, ispreferably. continued until the fibers In about,0..5 to. 2 6,%, based onthe weight ofconta n theetheri edfibers, of beta-propiolactone, reaction prod- 9b, cq n neduith ell los Suitable'solvents, for, such solutions comprise, liquidsv Wh LQh are ute stive solvents for Ctt rPIOPiOIaCtOne (i. e.,

are unreactive toward beta-propiolactone or cellulose and are capabeof dissolvingat least about 0.5 partof betapr piq ctnnepenper oisotventh Throughout thespecificationand claims the term parts efers to. p rts. by; w ght-v Examplcs of suitable, solvents include hydrocarbons such as; benzene, xylene, and thenormal, branch-chain, or cyclic hexanes, halohydrocarbons such as carbon tetrachl9ride,, ch1oi ofo rm,' tetrachloroethane, and chlorobenzone, and ketones such as acetone, methyl iso-butyl ketone,

andmet hyl iso -propyl ketone, andethers such asv dioxane and the likeorganio solvents. The use of. solutions of beta-propiolactone containing from about to 20 parts ducted by immersing the etherified cellulose fiber in the solvent solutionmaintained at the reaction temperature sired.

,The reactivity of the etherified fibers towards betaprop olactone is, appreciably improved by the presence of a relatively small amount ofwaterin intimate contact.

with the fibers The amount ofwater can be varied widely but in general,; the amount left in wetted. fibers by the mechanical removal of excess moisture, using,

textile apparatus such as squeeze, rolls orcentrifuges. is particularly suitable. In a preferred embodiment of. this invention, cellulose fibers are, etherified, then wetted and mechanically-.fi'eed of excess liquid,,and.the moist fibers are reacted with beta-propiolactoneat a temperature of from about5 to l50 C.

The reactivityof, the etherified fibers is further improved whenthe water. in contact with the fibers contains dissolved alkali metal hydroxide. The use of alkali metal hydroxide concentrations of from about 5 to 50% and the methods ofpretreatingthe fibers with such a water solutionwhich are. more. fully described in our copending application No." 393,523 comprise another preferred embodiment of the present invention.

Beta-propiolactone is known to be capable of reacting in numerous ways. For example, it can etherify hydroxyl gro'u'pacsterifyhydroxyl groups, etherify carboxy groups, react with amino. groups, and polymerize. Presumably,

the .betaepropiolactone undergoes .a plurality of types of,

reactionsv when it is' reacted with the etherified cellulose fiberi'sin accordance withthis invention.

Following the beta-propiolactonc reaction, the fibers are preferably washed freeofuncombincd reactants with: an organic solvent capable of. dissolvingpolymers of beta-v propiolactone, for example, with solvents such as acetone, alcohol, or; dioxane. The washing subtsantially com- .pletely removes adhering beta-propiolactonepolymeric 4. produc s whichv are not, chemica ly. at ched. t thefih r. walls, and leaves the fibers with a soft, wool-like hand and feel.

When cotton fibers are: (l) etherified to yield cellulose ethers containing from about O .l to 1 ether radical per anhydroglucose unit; under mildconditions, that preserve the bulk" of the performance. characteristics. inherent in the intricate structure of the fibers; (2) then are reacted with beta-propiolactone at a temperature below about 150 C.; the etherificationandthebeta propiolactone reactions coact to add additional advantageous properties to the prepresent fiber properties that contributed to the fact that almost 70% of; the apparel fibers used in the United States in 1952 were cotton fibers. In accordance with this invention, these particularly valuable fibers can be produced by: etherifying cotton fibersby reactingsuch fibers in the presence of aqueous alkali metal hydroxide with an ctherifyingagent selected from the group con: sisting of--Z-aminoethylsulfuric acid, monochloroacetic acid, ethylene oxide, acrylonitrile, and'dimethyl' sulfate,

to produce cotton fibers containing from about 0:1- to 1.0

of the etherifying radicals ofthe etherifying agent-per anhydroglucose u1.tit 'and reacting the; etherified fibers with'beta propiolac tone by impregnating them with an aqueous liquid, which may be water or water containing aqueous alkali'metalhydroxide, immersing the imprcg-' nat'ed-fibers in a solution of beta-propiolactone in an unreactive liquid=-solventcontaining from about'5 to parts of beta-propiol'actoneper part of solution, and maintaining the solutionat from about 5 to 50C until'the fibers contain from about 10m 20%; based, on the weight of the etherified fibers, of beta-propiol'actone. reaction products combined with cellulose. v

Thechemically modified cellulosic fibers produced'by this invention are useful for substantially any of the wide:

variety of uses known for cellulosic fibers. Those con taining less than about ;one polar alkyl radical" per anhydroglucose unit are particularly useful as textile fibers wherever wool-glike properties and gpr operties such' as a heatresistance, an acid'induceddegradation resistance. and a wrinkle resistance markedly greater than those of' cotton fibers is important.

The fibers" produced by, this, invention can readily be.v

produced'in the form ofunsaturated compositions which undergo thereactions typical of organic compounds containingolefinic groups] These; unsaturated fibers .con-

stitutevaluableintermediates from which to prepare nu; merous different derivatives of cellulose in the form of cotton fibers.

Theun saturated fibers can be produced by subjecting the fibers producedby etherification and; beta-propiolactone reaction to' dehydration at moderately elevated temperatures.. Apreferredprocess of producing them, com

prises, immersingsuch fibers in a waterimrriiscible inert organic liquid,-*-reiiuxing theliquidpand isolating ,water3 fromthe liquid -returni'ng from the condenser; The

water immiscible solvents for beta-propio'lactone are pre-,

ferred-liquids for such-employment; The" dehydration is. preferably conducted at fromabout 50 -C;';to about '1C. The dehydration can be conducted by a wide variety of conventional procedures for dehydrating solid compositions atmoderately elevated temperatures, It can becondncted during-the reaction of the etherified cellulose; fiber-(withbeta-propiolactone; so that the betapropiolactone reacted fibers are subjected to'dehydration as they. are formed The followingexainples further illustrate; this invention.

XAMPLEJ 1 Weighed samples of thefollowing forms ofg'cotton fibers were; each reacted Wiflil beta-propiola'ctoney The samples .were each, immersedin about; 20 times their weightof a xylene solution of beta-propiolactone' contain-.

agenc es.

under atmospheric pressure forabout one hour. Each minutes with acetone, to remove. reactants. and byproducts, then dried and weighed. The amount by. whichthe weight of the samples was increased by the treatment is reported as percent weight gain in the following table.

The samples used were: (a) A skein of plain cotton thread, purified by extraction with monoethanolamine;

(b) a skein of mercerized cottonthread; (c) a piece of hydroxyethylated cotton cloth containing 9.25% C2H4O (prepared by reacting sodium-hydroxide-treated cloth with a 1.6% solution of ethylene oxide in carbon tetra chloride for 1 hour at 55 C.); (d) a skein ofcyanoethylated cotton thread containing. 2.3% N (preparedby reacting sodium-hydroxide-treated thread with acrylonitrile at 55 C.); (e) a piece of aminoethylated cotton cloth. containing 0.88% IN (prepared by padding cotton cloth with a solution of 20% ,2-aminoethy1 sulfuric acid in 40%. sodium hydroxidesolution andheating at 110 C. .for 30 minutes); (f) a skein of carboxymethylated cotton thread containing 0.07 sodium carboxymethyl groups per anhydroglucose unit (prepared by padding cotton thread with 15% monochloroacetic acid followed by treatment with 40% sodium hydroxide); and (g) a skein of partially methylated cotton thread containing 7.8% OCH: (prepared by reacting. sodium hydroxide-treated cotton thread with methyl sulfate in toluene).

Table of results Material: Weight gain percent Purified cotton 29.6 Mercerized cotton 24.5 Hydroxyethylated cotton 77.0 Cyanoethylated cotton..- 55.2 Aminoethylated cotton 88.5 Carboxymethylated cotton 57.9 Methylated cotton 38.8

EXAMPLE 2 Samples of cotton cloths which had beenhydroxyethylated, aminoethylated, and carboxymethylated in the manner described in Example 1, and a sample of plain cotton cloth, were padded to 131146% wet pickup of sodium hydroxide solution and then soaked in a 20% aqueous solution of beta-propiolactone for 1 hour at normal room temperature. After the treatment, the samples were extracted with boiling water to remove reactants and by-products, dried and weighed.

Table of results Wet Weight Material pickup of gain, per- N a 013% cent Hydroxyethyl cellulose (9.25% O H O) 143 23. 4 Aminoethyl cellulose (0.43% N 139 19. 8 Carboxymethylcellulose (D.S.: 0.08).. 146 22. 9 Plain cotton 131 8.7

EXAMPLE 3 A piece of plain cotton cloth and a piece of aminoethylated cotton cloth (containing 0.88% N, and prepared as described in Example 1) were treated with pure beta-propiolactone at room temperature for 1 hour.

. After extraction and drying, neither sample had gained When a piece of the same aminoethylated cotton cloth was padded to 59.4% wet pickup of water and then treated with excess pure beta-propiolactone at about 95 -99 C. for 1 hour; the weight gain was 149.8%.

EXAMPLE 4 Skeins of partially carboxymethylated cotton 7 2 thread containing 0.07 sodium carboxymethyl groups per anhydroglucose unit (prepared as described in Example 1) were treated with 20 times their weight of 10% betapropiolactone in xylene at refluxtemperature for various periods of time (160 min.). Weight gains shown in the table below indicate that thereaction (with the conditions used) was essentially complete after 20 minutes.

The thread before lactone-treatment was somewhat stitf; but was considerably softened after reaction with beta-propiolactone. This softening effect increases as the amount of beta-propiolactone substituents increases. When warm, the treated thread was much softer than it was at room temperature. This effect is possibly due to the thermoplastic properties of the beta-propiolactone substituents.

Reaction time Wt. gain Reaction time Wt. gain (min) (percent) (min. (percent) EXAMPLE 5 Skeins of partially carboxymethylated cotton 7/ 2 thread similar to those used in Example 4 were treated with 20 times their weight of various concentrations of betapropiolactone in xylene, at reflux, for 1 hour. Results are shown in the table below.

Cone. of BPL (percent): Weight gain (percent) 0 (control) 5 EXAMPLE 6 Cloth: Wt. gain (percent) Plain cotton 29.8

Mercerized cotton 16.8 Carboxymethylated cotton, acid form 11.3 Carboxymethylated cotton, sodium salt 181.5

EXAMPLE 7 Plain 12/5 sewing thread and carboxymethylated 12/5 thread containing 0.08 carboxymethyl groups per anhydroglucose unit (prepared as described in Example 1) in the form of the free acid and the sodium salt, were treated with beta-propiolactone to about 12% weight gain (after extraction with acetone to remove unattached polymer). The treated samples and an untreated sample of the etherified cotton thread were then extracted ten times with hot glacial acetic acid. The treated plain cotton retained 50% of its original tensile strength while the sodium salt of the treated etherified cotton retained 90% and the free acid form of the treated etherified cotton retained The untreated etherified cotton thread retained 65%. This showed that carboxymethylation and beta-propiolactone reaction coact to give enhanced protection against acetic acid degradation.

Atdupli ate1 stofrthe-tsamplesrused:imExamgle- 71 were exposed: torNQa gas -ini a; closedggdesiccator :for 6 hours;

The treated plain cotton retained: 70% of its tensile strength while the treatedacidctherified sample retained 100 andtthe. treated tsodiumr etherifiedisarnple retained 90%. The-untreatedzetherifieck sample! retained 52%..

' EXAMPLE 9' When part ofrtheabove-'rsamples were h'eated;:at;.l25- C, for 15 days, the-strength retention of; the treated etherified cotton was approximately; -10 -1 5 better. than that: of either the treated, plain-1 cotton 7 or the untreated i etherified, cotton.

We claim;

1, A. process comprising etheritying cellulosez; fibers:

with an etherifyingt-agentt selected from the; group consisting of aminoallcylsulfuric acid,- monochloroacetic acid, alkylene oxide, acrylonitrile,, and, alkyl sulfate,

until esterifiedcellulose fibers-lcontaining from about; 0. l. to 2.5 of the etherifying radicals of said etherifying ragentt per anhydroglucose unit are produced, the alkyls, group in each of said etherifying radicals having from 1 to 3 carbon atoms, and reacting thesaid etherifiedcellulose fibers with beta-propiolactoneat a tempcratureof from about 0 C. to, a temperature slightly below thedecorn-v position temperature of the fibers-until fibersareproduced,

containinggfrom about 0.5 to 126%, based on the weight of the etherified fibers,,of,, beta-propiolactone reaction products combined with the cellulose.

2. 'The process .oficlaim 1 wherein the etherifying agent is aminoalkylisulfuric acid;-.

3 .3 i The process of claim :2. wherein the; aminoalkyl :su: i

furic acid is 2.-,aminoethy1' sulfuric; acid:

4: *111e. ;acess; of claijn rwh'erein the etherifying agent is monochlo'roaeetie'acidw 5i"A .ip roces's comprising ethe'rifyiiig cotton fibersby' reactingsaid-'fibers'inthepresence ofaqueous"'alkalimetal" h'ydroxi'dewith; an eth'erifying agenfselectedfromth'c group-consisting ofaminoalkyl sulfuric acid; mon'ochloro aceticacid; alkyle'ne oxide; acrylonitril'; andialkyl' sulfate-until etherified' cotton fibers containing if from about (Ll to 14-0 of the; etherifying; radicals of said etherifying age'ntper' anhydroglucose unit"'are'-' p roduced,'- the alkyl group in' eacli of--said*"ethcrifyii1g radicals h'aving'from l to-*3 carbon atoms; and: reacting' the said" etherified cotton fibers with betapropiolact one"* by impregnating tlie'rnwith-water-to improve their'reactivity' towards beta propiolactone, immersing-"the so-imPreghated"etherified cottonfibersin a' solution ofb'eta-propiolactone in' air un= reactive liquid solvent containing trom about 5 to- 9 Spart's of b'eta propiolactoneper part of solutio'ny'and maintaining the solution" atfrom about 5 'to C: until thefibers containfromabout '10 to' 20% based on the weightof:' the original etherifi'ed* fibers, of b'e'ta-propiolactone reaction productscombined with the-cellulose-s beta-propiolactone.

7. The process of claim 5 wherein the etherifying agent.

is 2-aminoethylsulfu'ric acid.

8: Theprocessofclaim-S wherein-the etherifying :agent is'monochloroaceticacids" No references citedz- 

1. A PROCESS COMPRISING ETHERIFYING CELLULOSE FIBERS WITH AN ETHERIFYING AGENT SELECTED FROM THE GROUP CONSISTING OF AMINOALKYL SULFURIC ACID, MONOCHLOROACETIC ACID, ALKYLENE OXIDE, ACRYLONITRILE, AND ALKYL SULFATE, UNTIL ESTERIFIED CELLULOSE FIBERS CONTAINING FROM ABOUT 0.1 TO 2.5 THE ETHERIFYING RADICALS OF SAID ETHERIFYING AGENT PER ANYDROGLUCOSE UNIT ARE PRODUCED, THE ALKYL GROUP IN EACH OF SAID ETHERIFYING RADICALS HAVING FROM 1 TO 3 CARBON ATOMS, AND REACTING THE SAID ETHERIFIED CELLULOSE FIBERS WITH BETA-PROPIOLACTONE AT A TEMPERATURE OF FROM ABOUT 0* C. TO A TEMPERATURE SLIGHTLY BELOW THE DECOMPOSITION TEMPERATURE OF THE FIBERS UNTIL FIBERS ARE PRODUCED CONTAINING FROM ABOUT 0.5 TO 26%, BASED ON THE WEIGHT OF THE ETHERIFIED FIBERS, OF BETA-PROPIOLACTONE REACTION PRODUCTS COMBINED WITH THE CELLULOSE 